Thank you for posting your query at DoctorSpring.com
Your husband is suffering from spinning sensation/ vertigo. it is associated with positional changes.
He has aural fullness and headache also.
Most likely the diagnosis is benign paroxysmal positional vertigo(BPPV) only. It is definitely not
related to dehydration or mattress height.
so to get treated BPPV first it has to confirmed by postional test(dix halpike maneuver) and if
positive it can be treated with epley's maneuver, for this you can visit local ENT specialist. he can
examined left ear also.
Other investigations can help are audiogram (hearing test) and CT Brain plain to rule out other
Hope this helps